Tower reactor



b 0 y w INVENTORS 94511 fir R W F j vmwwowowmmwowo mm W Patented Dec. 5,1950 TOWER REACTOR Austin S. Brunics, Plandome, N. Y., and Marcel J. P.Bogart,- Teaneck, N. J., assignors to The Lu nmus Company, New York, N.Y., a corpora ion of D laware Application February 20, 1946, Serial No.649,060

2 Claims. 1

This invention relates to an improved apparatus for carrying out thehalogenation of an aromatic hydrocarbon and specifically relates to thechlorination of benzene. It is a continuation-in.- part of our copendingapplication, Serial No. 447,983, filed June 2-2, 1942, for Halogenationof Aromatic Hydrocarbons, which issued February 25, 1946, as Patent No.2,395,777. As is well known, chlorinated benzenes are, commonly used asa base material in the production of many chemicals. More particularly,phenol and other products are obtained by the suitable conversion ofmonochlorbenzene. The chlorination of henzene to produce substantialyields of'monochlorbenzene cannot be readily carried out, however,except. by the most careful control of the conditions of the reaction,particularly the tempera== ture, in order to prevent undue side reactios from taking place.

An important object of our present invention is to provide an improvedapparatus for specifically controlling the reaction between chlorine andbenzene whereby the maximum yield of, monochlorbenzene and the minimumyield of polychlorbenzenes are obtained.

Further objects and advantages of our invention will appear from thefollowing description of a preferred form of embodiment thereof taken inconnection with the attached drawing in which:

Fig. 1 is a vertical sectional view of the reaction vessel;

Figs. 2 and 3 are horizontal cross sections taken substantially on theline 22 and 3-4. of Fig. 1;

Fig 4 is a vertical section on the line 4W4 oi Fig. 3. t

The reaction vessel It comprises a vertical series of sections. Thelowest section II is the base or supporting section acting as thefounda. tion for the entire vessel and contains the hen zene feedchamber Ila having a benzene, inlet 25.. It is surmounted by severalreaction sections, ins

dicated at l2, l3 and I4. The uppermost section l5 may be termed thevapor disengaging section.

With a reaction such as halogenation of ar matic hydrocarbons, it ishighly desirable to provide optimum temperature control at the zone ofreaction, and we also find it desirable to pro vide for individual unitreplacement of appara= tus. For these reasons, the sections 12, I3 and Mare independen t,having tube sheets 5.2a, and iZb, 53a and 13b, and Maand Mb, respectively, to which the react on tubes 2 2'5 and .2 are 1?cured- These tubes a e n al gnment and pro vide for the desired flow ofreactants as hereinafter described. Each tube is filled with a suit ablecatalyst and packing 23, which may consist of any suitable material suchas ceramic or iron rings. We prefer to use Raschig rings or the like,and these may be treated with ferric chloride if desired.

A controlled inlet of the reactants (benzene and chlorine) to thesetubes can be accomplished most successively according to our inventionby bubbling the chlorine through a body of benzene. This may beaccomplished by introducing the benzene as a liquid into tubes 26 andthen feeding the chlorine as a gas under positive pressure into chamberZiia adjacent the bottom of the tubes 2!) through inlets 25. Manifolds27 may be used to interconnect all of the inlets .5, which are of equallength thereby assuring equal distribution of the gas.

The introduction of the mixture of benzene and chlorine into the lowerpart of the tubes 29 and the continuous movement of the reactants up..Ward through the tubes 26 as well as the tubes Z! and 22 assure acomplete and continuous reaction of the products. With the feed toreaction section l2, this section also becomes a feed section as well asreaction section.

The reaction sections i2, i3 and Hi are prefer-v ably so arranged withinthe reaction vessel ID that a suitable cooling medium can beindependently circulated about them in indirect heat exe changetherewith. This is most important as the reaction is exothermic and itis necessary to regue late the temperature of the reaction and toprevent side reactions from taking place. In the formation ofmonochlorbenzene, the reaction is best accomplished at temperatures of40 to C., and above this excessive formation of polychlorbenzenesresults. It is necessary precisely to control the cooling effect in therespective sections, as the separation of monochlorbenzene frompolychlorbenzenes is also difficult and expensive.

We have found that although water is the cheapest cooling medium, anon-reactive coolant such as cooled monochlorbenzene itself is superior.It is to be understood that the possible leakage of water into thereaction zone would result in the formation of an acid solution (of thehydrogen chloride present) which is so highly corrosive to ordinarymaterials of construction as to immediately cause damage that isaggravated with time. Using monochlorbenzene from some other part or theprocess or storage assures no damage due to lea a e.

S alan nle and. is rg no les 30, 30a. 3

am, and 32 and 32a, provide for the desired c001- ing. Suitablemanifolding may be provided, and coolant discharge nozzles 30a, Sid, and32a, respectively, may be interconnected. For example, the coolant maypass through the upper reaction sections I3 and M in series. Suitablevalves will be provided for regulating the flow of coolant and externalmeans, not shown, will be used to remove the heat therefrom. Baffles 38within the sections may also aid the suitable distribution of thecooling medium about the reaction tubes and. the entire reaction zonesurrounding the chambers 29a at the lower part of the tubes 2!} isdirectly cooled.

It will generally be necessary to remove the largest amount of heat inthe lowermost feed reaction section I2, and a close temperature controlin this section is necessary. For this purpose, inlet 30 can beinterconnected with a suitable temperature controller so that the flowof coolant through inlet nozzles 39 may be automatically controlled bythe exit temperature of reaction section 12. The entire reaction tubearea is surrounded by coolant for the quick and positive temperaturecontrol.

Benzene and chlorine reactants, as previously indicated, pass upwardlythrough the reaction tubes and come into contact with the packingtherein. This packing provides for a substantially complete mixing ofthese reactants and also insures that the reactants come into intimatecontact with each other. The reaction takes place, for the most part, inthe lower portion of the reaction tubes, although the reaction tubes aresufiiciently long so that the reaction is substantially complete by thetime that the reactants have traversed the length of these tubes.

The mixture of reaction products discharged from the reaction tubes ispartially in the liquid and partially in the vapor state. This reactionmixture consists of chlorbenzenes, unreacted benzene, and hydrogenchloride. The liquid portion of the reaction mixture is removed overweir 39 through nozzle 48. The vapor portion of the reaction mixture isremoved from reaction vessel I!) through nozzle ll and is passed to acondenser, not shown, wherein the vaporized benzene and chlorbenzene arecondensed. The condensed material is separated from the uncondensedhydrogen chloride and the condensate may be returned through line 45 tothe vapor chamber section I5. The uncondensed hydrogen chloride will beremoved in its gaseous state to a suitable recovery system or the like.The condensate reintroduced into section l through nozzle d5 dischargesthrough conduit 48 alongside of the wall of the zone [5 which isexpanded in diameter not only to provide for the weir 39 but also toallow adequate vapor volume and prevent foaming and liquid carry over.

This arrangement materially aids in the recovery of the liquid product.

The liquid portion of the reaction mixture removed through nozzle 40 ispassed to a suitable heater, not shown, wherein a portion of this liquidis heated to the neighborhood of the boil ing point to remove as muchhydrogen chloride as possible. The vaporized portion comprises hydrogenchloride together with some benzene and chlorbenzene vapors, and may beadmixed with the vapors from line 4|. The liquid portion may be removedas product.

We have found it preferable to fabricate reaction vessel It as anintegrated unit as shown. In this manner, not only is a compact vesselprovided, but the amount of space necessary for the equipment ismaterially reduced. As indicated, the bottom of the feed chamber sectionI! may be provided with a suitable drain 6B. Ordinarily, we find itdesirable to operate the reaction section under a slightsuperatmospheric pressure.

It may be found desirable to introduce additional amounts of chlorine atintermediate points along the length of the reaction tubes therebyreducing the temperature of the reaction. This may be accomplished byintroducing such material into the chambers 20a through perforatedhalogen inlet tubes 26 or by using the secondary reaction section l3 asa mixing section for the feed of a part of the halogen. The proportionof halogen to be introduced at section [2 as compared to section Itwill, of course, depend on the benzene iiow rate, the temperature, andthe nature of the reaction desired.

It is to be noted that the spacing between the tube sheets, and thusbetween the ends of the tubes, permits an equalization of flow ofreactants through the tubes. Temperature controls H and 72 representedas temperature wells are also used in such chambers so that a carefultemperature control can be maintained in all parts of the system.

Although We have shown and described a preferred form of embodiment ofour invent on, it will be understood that modifications may be madethereto; therefore, only such limitations as appear in the claimsappended hereinafter should be made.

We claim:

1. Apparatus for conducting a reaction between a liquid and a gas,compris ng an elongated vertically extending shell, vertically spacedtransverse partitions dividing saidshell into a plurality of superposedchambers. the lowermost one of said chambers form ng a feed chamber fora liquid reactant, the chamber immediately above it forming a reactionchamber and the remaining chambers forming s condary reaction chambersand a vapor-disengaging chamber above the uppermost one of the reactionchambers, vertically extending transversely spaced tubes within each ofsaid reaction chambers and fixed in the partitions forming the upper andlower ends of the chamber, a support in each of said tubes for a fixedbed of catalyst, a gas delivery manifold above the tubes of thelowermost reaction chamber, a plurality of gas-distributing conduits,substantially smaller than the reaction tubes, leading from saidmanifold and extending into the upper ends of the respective reactiontubes and downwardly along a major portion of the length thereof andopening thereinto, the tubes of the lowermost reaction chamber openinginto the feed chamber to receive the liquid reactant therefrom, andmeans to pass a cooling medium in contact with the exterior of the tubeswithin each reaction chamber the intermediate adjacent ends of the tubesbeing in liquid cominto said shallow chamber, a support in each of saidtubes for a. fixed bed of catalyst, a gas delivery manifold within saidshallow chamber, a plurality of gas-distributing pipes substantiallysmaller than the reaction tubes, leading from said manifold andextending from the upper end of the respective reaction tubes of theprimary reaction chamber downwardly along a major portion of the lengthof said tubes and opening thereinto and establishing a uniform gas flowto the lower ends thereof, the tubes of the lowermost reaction chamberopening into said feed chamber to receive the liquid reactant therefrom,and to permit contact at the lower part with the gas therein, said gasdistributing pipes being spaced from the reaction tubes a sufficientamount to permit the reactants to pass upwardly therein and findependentmeans to pass a heat exchange REFERENCES CITED The following referencesare of record in the 10 file "of this patent:

UNITED STATES PATENTS 1 Number Name Date "1,915,077 Wagner June 20, 19332,298,593 Rubin et al Oct. 13, 1942 2,385,200 Friedel Sept.- 18, 1945

1. APPARATUS FOR CONDUCTING A REACTION BETWEEN A LIQUID AND A GAS,COMPRISING AN ELONGRATED VERTICALLY EXTENDING SHELL, VERRTICALLY SPACEDTRANSVERSE PARTITIONS DIVIDING SAID SHELL INTO A PLURALITY OF SUPERPOSEDCHAMBERS, THE LOWERMOST ONE OF SLAID CHAMBERS FORMING A FEED CHAMBER FORA LIQUID REACTANT, THE CHAMBER IMMEDIATELY ABOVE IT FORMING A REACTIONCHAMBER AND THE REMAINING CHAMBERS FORMING SECONDARY REACTION CHAMBERSAND A VAPOR-DISENGAGING CHAMBER ABOVE THE UPPERMOST ONE OF THE REACTIONCHAMBERS, VERTICALLY EXTENDING TRANSVERSELY SPACED TUBES WITHIN EACH OFSAID REACTION CHAMBERS AND FIXED IN THE PARTITIONS FORMING THE UPPER ANDLOWER ENDS OF THE CHAMBER, SUPPORT IN EACH OF SAID TUBES FOR A FIXED BEDOF CATALYST, A GAS DELIVERY MANIFOLD ABOVE THE TUBES OF THE LOWERMOSTREACTION CHAMBER, A PLURALITY OF GAS-DISTRIBUTING CONDUITS,SUBSTANTIALLY SMALLER THAN THE REACTION TUBES, LEADING FROM AID MANIFOLDAND EXTENDING INTO THE UPPER ENDS OF THE RESPECTIVE REACTION